Some of the giving in Buddhism is accompanied by ritualized behavior, and the observance of certain rules and restrictions. If people don’t know those rituals and rules, the experience for both participants is likely to be awkward and embarrassing.
Besides parents raising their children in certain ways, my understanding is that in Asian Buddhist countries, the kids will probably attend some kind of “Sunday school” classes for years, where all the chants, rituals and etiquette involved in customary Buddhist lay practice are taught and become second nature, and also the basic theory or motive behind the giving is developed and explained, along with an explanation of what lay people need to know about the monks’ rules, and some edifying stories of famous givers and lay supporters. For the western convert, all of this cultural background literacy is missing.
The monks don’t want to talk about this stuff, because it is not really their role . They are supposed to take what is given, and not tell people how to do the giving. But if there is no formal program of lay education, everything has to be picked up haphazardly and gradually.
If the western convert has childhood experience with another religion, the customs around giving could be very different. In my Catholic upbringing, we were taught to put money inside a sealed envelope, and discreetly place the envelop on the basket or plate so that nobody can see the amount. The idea of crawling on one’s knees in front of everybody with a tray full of vegetables, a giant bag of rice or a case of juice drinks is a new experience!